DESCRIPTION (Verbatim from the Applicant's Abstract): Early diagnosis of cancers is the key to improved treatment and survival rates of cancer patients. Upon cancerous transformation, the molecular composition and morphology of the tissue change, leading to altered optical characteristics of the tissue. Optical spectroscopic techniques thus provide a promising methods for fast, in situ cancer diagnosis. The long-term objective of this project is to develop a new optical technique, two-dimensional fluorescence correlation spectroscopy, for early detection of cancers. Combining both spectral and time resolution, the new technique resolves fluorescence into contributions of the tissue components and provides much better contrast between the normal and diseased tissue than steady-state fluorescence methods. The research project has two components. (1) Two-dimensional fluorescence correlation spectroscopy will be used to examine tissues at various histopathological conditions. Statistical analysis of the spectral library will establish quantitative criteria for cancer diagnosis. (2) Spectrally-resolved fluorescence imaging and time-resolved fluorescence spectroscopy will be employed to study the tissue biology. The fluorescence emission spectrum will be monitored for every pixel in the tissue. Fluorescence decay characteristics reveal the molecular environments in malignant lesions. Three- dimensional images of chemical composition of the tissue can be constructed from these studies. This understanding of molecular and morphological changes of the tissue upon cancerous transformation will guide the development of diagnostic techniques. With significantly enhanced contrast, two-dimensional fluorescence correlation spectroscopy may lead to a noninvasive method for early cancer diagnosis.